4.1 Properties of Minerals


Vocabulary


Ignorance: a mineral cannot arise from materials that were once part of a living thing
Crystal: the repeating pattern of a mineral 's particles form a solid
Element: a substance composed of a single kind of atom
Compound: two or more elements are combined so that the elements no longer have a distinct properties
Mohs hardness scale: this scale ranks minerals from softest to hardest
Streak: a mineral that is the color of its powder
Cleavage: a mineral that splits easily along flat surfaces
Fracture: describes how a mineral looks when it breaks apart in an irregular way
Flourescence: minerals that glow ultraviolet light
Mineral: has to be naturally occured, inorganic solid that has crystal structure, and chemical composition


Outline


  • What is a Mineral?
    • naturally occurring
      • to be called a mineral, it has to be naturally occurring
      • cement,brick,steel and glass are not classified as minerals because they can be found in Earth's crust
    • inorganic
      • coal naturally forms in the crust
      • geologists don't classify coal as an mineral
      • it is made up from remains of plants from the past and animals from a long time ago
    • solid
      • a mineral is always a solid and has a definite volume
      • the particles that make up a solid cannot flow freely
      • it is packed really tight unlike liquids
      • a solid keeps its shape
    • crystal structure
      • the particles of a mineral line up in a pattern that repeats over and over again
      • sometimes you can see the crystal structure by itself
      • you have to look under a microscope on to see the crystal structure on some of them
    • definite chemical composition
      • it contains certain elements in certain proportion
      • all the atoms of the of the same elements have the same physical property and chemical
  • Identifying Minerals
    • every mineral has specific properties to identify it
    • hardness
      • to find the hardness, you should scratch the mineral to another mineral
    • color
      • on some minerals you can identify the color by its physical property
      • some minerals have colors that does not match the mineral
    • streak
      • you can observe streak by rubbing the mineral by rubbing it against a tile
      • the tile is called a streak plate
    • luster
      • minerals that contains metals are shiny
      • there are several other names for luster
      • names: earthy, waxy, and pearly
    • density
      • one way to identify the weight of a mineral is to feel it with your hands
      • using your hands with your weight is a rough measure of density
      • geologists use a balance to measure the density
      • it is also put into the water to identify how much water it displaces
      • dividing the sample's mass by its volume gives the density of the mineral
    • crystal systems
      • the crystals of each mineral grow atom by atom to form the mineral's crystal shape
      • geologists identify these minerals into six groups
      • crystals that grow in open space can almost form perfectly
      • crystals that grow in small space are often incompletely formed
    • cleavage and fracture
      • whether a mineral has cleavage, it all depends on how the atom in the crystal is arranged
      • geologists use a lot of different terms to describe fracture
    • special properties
      • fluorescence
      • electrical properties

Diagram





4.1_diagram.jpg